We would need to redesign the rear of the current machine.
We use vertical shaft engines, the Kubotas are all horizontal, and of course the Kubota is a rather large engine to put in the rear of that unit.
As we are adding engines to the current line up, we are expanding your options, a diesel is in the future I would think....

On a side note,
How many here use diesels in there mid mount Z's and what mfg and deck size, and what did you pay for them ?

grassdaddy,
If you want a kubota in a midmount ZTR, then go look at the Grasshopper midmounts. You can get them with either the 21hp Kubota diesel, or the 28hp Kubota diesel. Both are great machines. I own one of each. Grasshopper has a long histery of using Kubota diesels in their mowers.

I have,i like the outfront hop also.our dealer is a super good guy too.i've been lookin at the kubota zd28f with fab. deck.kubota is offering 0%apr.--i rode a super z at nashville its fast,rides great,awesome built deck,reps were very nice.if they come out with a oilburner i'll probably get one.